The present invention relates generally to clamping devices and more specifically, to clamping devices having a locking type mechanism which are particularly adapted for use by well drillers, well repairmen and pump installers in securely holding pipes when servicing wells or installing pumps.
A wide variety of clamping devices having locking type mechanisms are known in the art. For example, U.S. Pat. No. 2,379,107 to Scheck discloses a clamp wrench having a stationary jaw fixed to the shank, a movable jaw slidably mounted on the shank, and means for moving the movable jaw comprising a lever pivotly attached to the movable jaw, a toggle link, a rotatable screw for relative adjustment of the movable jaw and a movable block on the shank attached to the toggle link and the screw. In U.S. Pat. No. 2,651,959 to Harrington, disclosed in a sliding jaw vise including a base having a fixed and movable jaw attached thereto, an adjustable threaded push rod attached to the movable jaw, and a link pin and lever which lock the movable jaw against a workpiece. In the vise the Harrington patent, the movable jaw is adjustable on the push rod by the provision of a series of holes and a drop pin.
Furthermore, U.S. Pat. No. 2,692,520 to Hayes discloses a toggle operated pipe holder where the toggle mechanism is adjustable by means of a threaded rod. In a toggle lever actuated sliding jaw vise as taught by U.S. Pat. No. 2,841,196 to Zazdrzyk, a movable jaw is pulled against the fixed jaw by the toggle mechanism. U.S. Pat. No. 3,152,466 to Johnson discloses a vise comprising a support having a fixed and movable jaw attached thereto, a threaded adjustment rod attached to the movable jaw, and a toggle mechanism pivotly attached to the support and to the threaded rod, the threaded rod acting as a lever for locking the toggle mechanism.
However, none of the above mentioned patents appear to disclose a clamping device which includes the combination of features of an adjustable mechanism to lock a movable jaw relative to a fixed jaw by pulling as opposed to pushing the movable jaw toward the fixed jaw by means of a structure including an inwardly moving lever which pulls the movable jaw toward the fixed jaw.